One of the bigger changes to IIS 6 is the conversion of the IIS Metabase from a binary (bin) file to an XML file. What this allows is the editing of the IIS Metabase while IIS is running, similar to httpd.conf in Apache.

The metabase files for IIS 6 are located at %SystemRoot%\System32\Inetsrv and are named MetaBase.xml - which is the XML file that contains IIS configuration settings. MBSchema.xml - which is the metabase schema which which defines the elements and sets the data types. MetaBase.xml can be edited by an administrator, while IIS is running. When an administrator is editing the XML file while IIS is running, the actual changes are made to the file loaded into memory and written to disk every 5 minutes. To enable live editing of the metabase, open up the Internet Information Services MMC and right-click on the server, then select Properties. Tick the box next to Enable Direct Metabse Edit and click Apply.

 There is one additional directory, %SystemRoot%\System32\Inetsrv\History, that contains versioned copies of these files. These files can be used to revert the changes you made to the metabase when something does not work as expected. Finally, you may also see some error files in %SystemRoot%\System32\Inetsrv\History. These error files occur when the metabase gets corrupted during editing.